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Without specific information such as the air carrier(s) between EVV and VIE, the fare buckets and fare rules, it is hard to provide solid information.

But, as a general matter, most carriers prohibit ticketing which has the effect of evading fare rules including advance purchase, location of purchase, minimum stay and the like. Why you are doing this is unimportant. All the carrier(s) care about is that your booking pattern violates the COC (contract) to which you agreed.

Your TA ought to have caught this as it is what it is paid to do. And, it is entirely correct that the carrier(s) may well cancel all tickets and also take action against your FF account(s). Alternatively, the carrier(s) may also debit the TA for the cost of tickets which do comply. But, that is not your problem.

Why not come back with sufficient information and you can get some specific assistance.